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If you get 30/50 winners (60%) then your deviation from the random 50% (25:25) is 5. This deviation gives 5^2 or 25/25 for winners and 25/25 for losers or 1 + 1 = 2 with one degree of freedom. This is not significant at the 5% level.

This means that getting 60% winners on this small sample will happen by chance simply because you got lucky.

If you get 60% winners from 100 then the chi square is 2+2 or 4 and is significant at the 5% level. This means that less than once in 20 times will such a result occur by chance if you are merely lucky and only picking at the 50% rate.

As I said before 6 losers in a row is significant for a 60% win rate but I feel the above chi square test which becomes marginally significant after 100 samples for a 60% capper is a better test.

Since few cappers can maintain a 60% win rate and since the sample size needed increases greatly as one tries to measure a smaller difference from 50% you can see that large samples are needed. In fact one NFL season becomes meaningless for ATS picks.

First thing for me is to CONCENTRATE on a sport or sports that you KNOW you will win. The only sport that fits that criterion for me is College Football. I will play way more on CFB than any other sport. Most of my play size is predicated on feel. With the internet and reduced juice shops it has made winning a little easier. To break even with -110you need to win 52.38%. With -105 you need to win 51.22%. It is VERY important to use reduced juice and Shop, Shop and Shop some more! Got off topic a little but every one might use a different way. Use what works for you. OBTW, I will NOT wager any serious money on ANY pro sport! Keep a separate log on how you do on pro sports in relation to college sports. You will be surprised. Great topics, Fish. LT

great post coach LT...great thread as well...I specialize in college football and like coach LT feel comfortable betting larger ammounts...I play smaller in college hoops (which I feel is much more difficult to handicap do to the increased number of uncontrolled variables vs. college football) but have been getting better with each year...

never chasing, not drinking when I gamble, using reduced juice books, studying stats and tendencies, and betting teams I've seen play (didn't bet any Sun Belt games in football, and only will bet 13 of the 30 conferences in basketball) have been keys to success for me...

If you get 30/50 winners (60%) then your deviation from the random 50% (25:25) is 5. This deviation gives 5^2 or 25/25 for winners and 25/25 for losers or 1 + 1 = 2 with one degree of freedom. This is not significant at the 5% level.

The Kelly criterion is a money-management formula of passionate interest (and controversy) to card players, sports bettors, investors, hedge fund managers, and economists. One topic you won't find much about on the Web is Kelly himself. In the hope of remedying that, I've started this page. I am the author of a book, Fortune's Formula (Hill and Wang, 2005), in which John Kelly is a key figure. Kelly was a Bell Labs physicist and computer scientist of diverse accomplishments and interests. I imagine he would have thought it odd that his name would be linked above all to his "gambling formula." <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>So who was Kelly? How did he get a money-management formula named after him?<o:p></o:p> <o:p></o:p>John Larry Kelly, Jr. (1923-65), was born in Corsicana, Texas. He came of age during World War II and spent four years as a flyer for the Naval Air Force. A capable pilot, he survived a plane crash into the ocean. Kelly did undergraduate and graduate work at the University of Texas, Austin. His 1953 Ph.D. topic was an "Investigation of second order elastic properties of various materials." This led to work in the oil industry. As Kelly told the story, his employer, a successful wildcatter, would smell the soil and drill by instinct, ignoring Kelly's carefully prepared scientific recommendations. The oilman's hunches were so unerring that Kelly decided he was in the wrong line of work. He accepted a job offer from Bell Labs. <o:p></o:p>Bell Labs, in Murray Hill, New Jersey, was one of the world's most prestigious scientific research centers. Kelly was barely 30 when he arrived. His Texas drawl set him apart (oddly, it seemed to grow deeper the more years he lived in New Jersey). So did his interest in guns. Kelly belonged to a gun club and counted a Magnum pistol among his prize possessions. Kelly was married to the former Myldred Parham. Myldred was herself a pilot and had been the executive officer of a MASH unit in India during the war. As a couple, the Kellys were ruthless tournament bridge players. They raised three children -- Patricia, Karen, and David -- in a suburban house in Berkeley Heights, New Jersey. <o:p></o:p>Kelly was "a lot of fun, the life of the party," I was told. Another associate described him as a "wild man." One tale claims that Kelly once earned a reprimand by prankishly flying a plane under the George Washington bridge. In another story, Kelly was at a conference on Cape Cod where a new rocket-powered ejection seat for pilots was being shown. Kelly decided it would be interesting to see if the seat really worked. He and several others put the seat in the back of a convertible and drove around Cape Cod looking (unsuccessfully) for a suitable place to launch it. <o:p></o:p>Kelly was a chain-smoker. Even in the family's home movies, Kelly is puffing away as he watches the children in the pool. Daughter Karen Kelly recalls that "Not only did we have guns and rifles in our house, but my father also had equipment to make bullets. He used to entertain people with shooting bullets with plastic or gummy inserts into a stone wall in the house. My mom said it was annoying to get them out."<o:p></o:p>One of Kelly's best friends at Bell Labs was a fellow Texan, Ben Logan. Each morning, Kelly and Logan would make coffee, then go into Logan's office. Kelly would immediately put his feet up on the chalk rim of the blackboard and light up a cigarette. Faced with a difficult problem, Kelly would think a moment, take another drag, and say something showing the most amazing insight. Many rated Kelly the smartest person at Bell Labs next to Claude Shannon himself. <o:p></o:p>Shannon was in a class by himself. He had single-handedly created the abstract theory of communication called information theory. Shannon presciently realized that computers could express numbers, words, pictures, audio, and video as strings of digital 1s and 0s. Information theory underlies the Internet and today's wired, and wireless, world. <o:p></o:p>At Bell Labs, Kelly was working on data compression schemes for the still-young medium of television. This brought him into Shannon's new field. Kelly made an ingenious connection between information theory, gambling -- and television. <o:p></o:p>On June 7, 1955, American television debuted a new quiz showcalled The $64,000 Question. The show was a sensation. It captured as much as 85 percent of the viewing audience and led to dozens of copycat shows. Kelly heard about a peculiar scam in the news. Some viewers of The $64,000 Question were placing bets on which contestants would win. The show was produced in New York and aired live on the East Coast. It was delayed three hours on the West Coast. According to the news story, one West Coast gambler learned the winners by phone and placed his bets before the West Coast airing.<o:p></o:p>Thinking about this convinced Kelly that a gambler with "inside information" could use some of Shannon's equations to achieve the highest possible return on his capital. Shannon was intrigued by this application and urged Kelly to publish his finding. Kelly's article appeared (under the opaque title "A New Interpretation of Information Rate") in a 1956 issue of the Bell System Technical Journal. <o:p></o:p>Kelly wryly presented his idea as a system for betting on fixed horse races. A "gambler with a private wire" gets advance word of the races' outcomes. The natural impulse is to bet everything you've got on the horse that's supposed to win. But when the gambler adopts this policy, he is sure to lose everything on the first bum tip. Alternatively, the gambler could play it safe and bet a minimal amount on each tip. This squanders the considerable advantage the inside tips supply.<o:p></o:p>In Kelly's analysis, the smart gambler should be interested in "compound return" on capital. He showed that the same math Shannon used in his theory of noisy communications channels applies to the gambler. The gambler's optimal policy is to maximize the expected logarithm of wealth. Though an aggressive policy, this offers important downside protection. Since log(0) is negative infinity, the ideal Kelly gambler never accepts even a small risk of losing everything.<o:p></o:p>You don't even have to know what a logarithm is to use the so-called Kelly formula. You should wager this fraction of your bankroll on a favorable bet: <o:p></o:p>

edge/odds<o:p></o:p>

The edge is how much you expect to win, on the average, assuming you could make this wager over and over with the same probabilities. It is a fraction because the profit is always in proportion to how much you wager. At a racetrack, the edge is diminished by the track take. When your edge is zero or negative, the Kelly criterion says not to bet.<o:p></o:p>Odds means the public or tote-board odds. It measures the profit if you win. The odds will be something like 8:1, meaning that a winning wager receives 8 times the amount wagered plus return of the wager itself. <o:p></o:p>In the Kelly formula, odds is not necessarily a good measure of probability. Odds are set by market forces, by everyone else's beliefs about the chance of winning. These beliefs may be wrong. In fact, they have to be wrong for the Kelly gambler to have an edge. The odds do not factor in the Kelly gambler's inside tips. <o:p></o:p>Example: The tote board odds for Seabiscuit are 5:1. Odds are a fraction -- 5:1 means 5/1 or 5. The 5 is all you need.<o:p></o:p>The tips convince you that Seabiscuit actually has a 1 in 3 chance of winning. Then by betting $100 on Seabiscuit you stand a 1/3 chance of ending up with $600. On the average, that is worth $200, a net profit of $100. The edge is the $100 profit divided by the $100 wager, or simply 1. <o:p></o:p>The Kelly formula, edge/odds, is 1/5. This means that you should bet one-fifth of your bankroll on Seabiscuit. <o:p></o:p>This version of the formula does not take into account the effect of one's own bet on the odds. It has the virtue of being easy to remember and applicable to other forms of gambling like blackjack. By always making the Kelly bet, you increase your bankroll faster than with any system. That's the good news. The bad news is that it's a rough ride. Downward plunges of wealth are frequent and steep. This can be rectified through diversification (as in team play in blackjack, or at a hedge fund, where the manager makes many simultaneous "bets" with low correlation). For the lone player betting on a single hand or horse, the Kelly formula demands guts and patience -- hence the controversy. Many have found the "half Kelly" strategy to be a good compromise. You bet half of edge/odds. This achieves ¾ the compound return of Kelly betting with much less volatility. <o:p></o:p> <o:p></o:p>Kelly had originally titled his article "Information Theory and Gambling." That bothered some AT&T executives, as did his mention of a "private wire." Throughout the twentieth century, AT&T had leased wires to organized crime figures who ran "wire services" reporting racetrack results to bookies. Even in the 1950s, bookies were still big customers. The executives feared the press might conclude from Kelly's article that Bell Labs was doing work to benefit illegal gamblers. They pressured Kelly to change the title of his paper to "A New Interpretation of Information Rate." <o:p></o:p>In fact, the executives didn't have much to worry about. Virtually no one took much note of the article when it first appeared. The practical application of the Kelly criterion began in the early 1960s, after MIT student Ed Thorp told Shannon about his card-counting system for blackjack. Shannon referred him to Kelly's article. Thorp used it to compute optimal bets in blackjack and later in the securities markets. It was Thorp's success as hedge fund manger that made Wall Street start to take notice of the Kelly criterion. <o:p></o:p> <o:p></o:p>Kelly died tragically young, of a brain hemorrhage at the age of 41. He was by then the head of Bell Labs' information coding and programming department and the author of several patents. Kelly has one further claim to fame. In 1961 Kelly and colleague Carol Lochbaum demonstrated a new voice synthesis system by making a recording of their machine singing the song "Daisy Bell," better known as "Bicycle Built for Two." <o:p></o:p>It was the latter that inspired the death scene of the computer HAL in Stanley Kubrick's film 2001: A Space Odyssey. Science-fiction writer Arthur C. Clarke had visited Bell Labs in the mid 1960s and heard Kelly's recording. In Clarke's screenplay, HAL is unplugged and reverts to a childish state, singing the same song that Kelly's computer did. <o:p></o:p> <o:p></o:p>

Remove a marble, take note by writing down what color it was and REPLACE, shake-up, and repeat the process.

Do this many, many times.

You may be amazed at how many streaks of RED you will have greater than four.............and this is picking 60% winners..........something even the best of the best professional sportsbettors cannot achieve longterm.

lol...recently I went about 70-30 with a new strategy. Statistics says this is 95% likely to be >60% over the long term, and 99.5% likely to be greater than 55% over the long term (aka classicly profitable)

I rationalized this in a similar method to the marbles...to put the chances into perspective I decided to flip a coin and see if I got heads. I'd have to flip it 4 heads in a row to be roughly 95%.

So I start flipping...heads...heads...heads...heads, a total of 11 heads in a row the very first time I sit down to try this. The coin wasn't misweighted, I flipped some more to check.

These kind of real world examples have provided a lot of perspective to me, and I'd recommend trying them to keep yourself grounded when you need it.

lol...recently I went about 70-30 with a new strategy. Statistics says this is 95% likely to be >60% over the long term, and 99.5% likely to be greater than 55% over the long term (aka classicly profitable)

I rationalized this in a similar method to the marbles...to put the chances into perspective I decided to flip a coin and see if I got heads. I'd have to flip it 4 heads in a row to be roughly 95%.

So I start flipping...heads...heads...heads...heads, a total of 11 heads in a row the very first time I sit down to try this. The coin wasn't misweighted, I flipped some more to check.

These kind of real world examples have provided a lot of perspective to me, and I'd recommend trying them to keep yourself grounded when you need it.

You just answered my next question, that being "What if you had a smaller sample size at a higher percentage, say 70%? What is the probability that the system is eventually viable at 55%?" Thanks.

If you get 30/50 winners (60%) then your deviation from the random 50% (25:25) is 5. This deviation gives 5^2 or 25/25 for winners and 25/25 for losers or 1 + 1 = 2 with one degree of freedom. This is not significant at the 5% level.

This means that getting 60% winners on this small sample will happen by chance simply because you got lucky.

If you get 60% winners from 100 then the chi square is 2+2 or 4 and is significant at the 5% level. This means that less than once in 20 times will such a result occur by chance if you are merely lucky and only picking at the 50% rate.

As I said before 6 losers in a row is significant for a 60% win rate but I feel the above chi square test which becomes marginally significant after 100 samples for a 60% capper is a better test.

Since few cappers can maintain a 60% win rate and since the sample size needed increases greatly as one tries to measure a smaller difference from 50% you can see that large samples are needed. In fact one NFL season becomes meaningless for ATS picks.

How do you feel about regression testing? That's my term for going back through a sample size to discover patterns that occur at a particular percentage (not to be confused with software regression testing). Let's say I buy a database of all NBA games played so far this season. Then I test for certain conditions such as spreads greater than +10 for home teams and I find that these situations hit greater than 55% of the time.

Is this valid modeling so that I can expect to blindly bet situations such as this? Or better yet, bet selectively by either applying additional conditions or just using my own gut feel.

I do believe there are situations in sports that fit this criteria. If one could find these situations I believe you would be successful.

How do you feel about regression testing? That's my term for going back through a sample size to discover patterns that occur at a particular percentage (not to be confused with software regression testing). Let's say I buy a database of all NBA games played so far this season. Then I test for certain conditions such as spreads greater than +10 for home teams and I find that these situations hit greater than 55% of the time.

Is this valid modeling so that I can expect to blindly bet situations such as this? Or better yet, bet selectively by either applying additional conditions or just using my own gut feel.

I do believe there are situations in sports that fit this criteria. If one could find these situations I believe you would be successful.

You betcha there are!!!

Some of which have never produced a losing record in any year for 20+ years.

How do you feel about regression testing? That's my term for going back through a sample size to discover patterns that occur at a particular percentage (not to be confused with software regression testing). Let's say I buy a database of all NBA games played so far this season. Then I test for certain conditions such as spreads greater than +10 for home teams and I find that these situations hit greater than 55% of the time.

Is this valid modeling so that I can expect to blindly bet situations such as this? Or better yet, bet selectively by either applying additional conditions or just using my own gut feel.

I do believe there are situations in sports that fit this criteria. If one could find these situations I believe you would be successful.

I have done a LOT of this. The simple formula to see if a win % is significant is multiplying the win % by 1 minus the win %, dividing by the number of samples, and taking the square root of that.

(sqrt (0.55 * 0.45) / 2000 )

Your win % is 99.7% within 3 times this number up or down from your mean. Your win % is 95% within two times this number up or down.

So the thing to keep in mind in regression analysis is that you are able to test a lot of different theories, and 1 out of every 20 will actually be a set that looks to be 95% significant, but is really just stumbled upon because you've tried 20 things.

A rule to use is that if you start to look at something that you *know* will affect win %, 2 standard errors from the mean is enough to start betting it. If you just start testin things that you *think might* affect it, and happen upon something you should have at least 2.5 standard deviations before betting on it.

How do you feel about regression testing? That's my term for going back through a sample size to discover patterns that occur at a particular percentage (not to be confused with software regression testing). Let's say I buy a database of all NBA games played so far this season. Then I test for certain conditions such as spreads greater than +10 for home teams and I find that these situations hit greater than 55% of the time.

Salain has noted that you'll make spurious hits if you are running large numbers of tests, while Fish asserts this is true but a closely guarded secret. Since Fish is a man of considerable experience I accept that there might be some such patterns.

My personal feeling is that you'll always find patterns but I would tend to reject them as being real (much like betting black on roulette after 13 reds). In NBA there's a guy progression betting for up to three games for a win after 3 losses and vice versa who is apparently doing well. I guess this is basically unrelated to spread but is based on motivation or other human factors. On the other hand I tend to laugh at posts that say team A hasn't lost ATS playing at home after a three day rest when the visiting team played the previous night and won. So what!

So my answer is that I would not accept any prior patterns without further analysis. The further analysis would be to use the pattern as a hypothesis and predict future events (after all that's what you want to do anyway). Then supposing you have a hypothetical 55% win system test the future results for deviation from 50% and 55% to see if it holds up.

Salain has noted that you'll make spurious hits if you are running large numbers of tests, while Fish asserts this is true but a closely guarded secret. Since Fish is a man of considerable experience I accept that there might be some such patterns.

My personal feeling is that you'll always find patterns but I would tend to reject them as being real (much like betting black on roulette after 13 reds). In NBA there's a guy progression betting for up to three games for a win after 3 losses and vice versa who is apparently doing well. I guess this is basically unrelated to spread but is based on motivation or other human factors. On the other hand I tend to laugh at posts that say team A hasn't lost ATS playing at home after a three day rest when the visiting team played the previous night and won. So what!

So my answer is that I would not accept any prior patterns without further analysis. The further analysis would be to use the pattern as a hypothesis and predict future events (after all that's what you want to do anyway). Then supposing you have a hypothetical 55% win system test the future results for deviation from 50% and 55% to see if it holds up.

I agree that a lot of analysis is needed once a pattern is found. What I would like to add to this is that a particular pattern may be viable, yet it may be a seasonal pattern. For example, after November in English Preimier soccer and after the all-star games in both MLB and the NBA there is a different dynamic. Teams play differently for some reason. In MLB there is a trading deadline after the All-Star game that mixes up the line-ups of the teams.

The point I'm trying to make with all of this is be careful when using a system that has been tested for the entire season. It may not be viable for a particular part of the season.

Some of which have never produced a losing record in any year for 20+ years.

When you find one, suggest you do not tell ANYBODY.

Just to let people know here, Fish isn't being selfish. He's just saying that if you tell someone your system and they bet using that system you stand to get lower odds on your bets or perhaps miss out on a bet if the line changes against you.

Fish, if someone finds a system like this, why not just bet huge amounts on the system? I would think that one could make tons of money. Sell your wife, mortgage your house, take out loans, anything to get a higher bet amount for an eventually bigger payout.

Thanks much to everyone who contributed to this thread. It is by far my favorite thread of 2006. Special thanks to Woody0, Cincy_ and Fish.

Fish, if someone finds a system like this, why not just bet huge amounts on the system? I would think that one could make tons of money. Sell your wife, mortgage your house, take out loans, anything to get a higher bet amount for an eventually bigger payout.

If you have a 90% shot of winning, and you bet your house, what if you lose? You are toast.

If you have a 90% chance of winning, and you bet $5 on it, you have not maximized your profit.

That is the ESSENCE of the Kelly Criterion. It calculates how much of your bankroll you need to wager to maximize your profit without totally exposing yourself. From Fishhead's post:

The natural impulse is to bet everything you've got on the horse that's supposed to win. But when the gambler adopts this policy, he is sure to lose everything on the first bum tip. Alternatively, the gambler could play it safe and bet a minimal amount on each tip. This squanders the considerable advantage the inside tips supply.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>

If you have a 90% shot of winning, and you bet your house, what if you lose? You are toast.

If you have a 90% chance of winning, and you bet $5 on it, you have not maximized your profit.

That is the ESSENCE of the Kelly Criterion. It calculates how much of your bankroll you need to wager to maximize your profit without totally exposing yourself. From Fishhead's post:

The natural impulse is to bet everything you've got on the horse that's supposed to win. But when the gambler adopts this policy, he is sure to lose everything on the first bum tip. Alternatively, the gambler could play it safe and bet a minimal amount on each tip. This squanders the considerable advantage the inside tips supply.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>

cincy_:

I have had this problem recently. When I go on a winning streak I have a tendency to bet amounts that are too large, thinking I am maximizing my profit. It is important to find an amount that will not bankrupt you once you start losing.

However, when I mentioned selling my house my intent was not for just one bet or a few bets. What I was wondering was if you have a valid system why not put as much money as you could into that system? I would like to stress here that it doesn't mean to throw all your money into a few bets. Certainly putting as much money into bets of a valid system would gain you more money in the long run.

[quote=quantumleap]Just to let people know here, Fish isn't being selfish. He's just saying that if you tell someone your system and they bet using that system you stand to get lower odds on your bets or perhaps miss out on a bet if the line changes against you.

Fish, if someone finds a system like this, why not just bet huge amounts on the system? I would think that one could make tons of money. Sell your wife, mortgage your house, take out loans, anything to get a higher bet amount for an eventually bigger payout.

Thanks much to everyone who contributed to this thread. It is by far my favorite thread of 2006. Special thanks to Woody0, Cincy_ and Fish.[/quote]

Because there will be a RISK OF RUIN involved and a mathematical STANDARD DEVIATION to this sort of system, SO SOME TYPE OF LIMITATION must be administered. However, you are correct in assumming that one should attempt to EXPLOIT these situations as much as possible WITHOUT THE RISK OF RUIN when they present themselves........or knowing the percentages of this risk of ruin and wagering an amount that will provide the best for ones PERSONAL tolerance for ........risk vs reward, risk of ruin(or loss) potential, financial gain, etc., etc..........that is a FUNDAMENTALLY SOUND FINANCIAL STRATEGY.

Obviously more than a few of us here have found some juicy nuggets over the years and have been rewarded more than adequately..........and it is safe to say there are many in abundance currently. The majority of these are how the true professionals walk home with RELATIVELY EASY CASH year in and year out.

Glad to hear you are enjoying this thread, your contributions to it have been very thought provoking on this end and I thank you.

I've been spending the last 3 years trying things here and there only to fail with all except a couple systems. I figured that it would be a good learning experience and it would provide entertainment. However, finding winning systems by experimentation is far too costly than betting needs to be.

I have resolved myself to find winning systems using analysis of existing data, rather than trial-and-error. Don't get me wrong, I feel using trial-and-error has given me an insight into sports betting that I could not get using systems alone.

I will follow a couple winning cappers here and will continue to use the systems I have found personally. But no more will I continue to experiment using trial-and-error which has been the bulk of my bets (and thus losses) so far.